The present invention relates to an image recorder implemented by an electrophotographic or an electrostatic recording procedure and, more particularly, to a cleaning device for such an image recorder in which a cleaning blade for removing remaining toner from a photoconductive element can be positioned relative to the photoconductive element with accuracy.
An electrophotographic copier, facsimile apparatus, laser printer or similar image recorder of the kind described includes an image carrier or photoconductive element for forming an electrostatic latent image thereon. After the latent image on the photoconductive element has been developed by toner, the resulting toner image is transferred to a paper. A prerequisite with this kind of image recorder is that toner remaining on the photoconductive element after the transfer of a toner image be removed. A cleaning device used to meet this requirement usually includes a cleaning blade and holds an operating edge of the blade in pressing contact with the surface of the photoconductive element during cleaning, whereby toner remaining on the photoconductive element is scraped off. In order that the edge of the cleaning blade may be accurately pressed against the surface of the photoconductive element with an adequate force, it is necessary to position the cleaning blade accurately relative to the photoconductive element.
A prior art cleaning device includes a tank for collecting the toner scraped off by the cleaning blade and which is rotatable about a shaft relative to a frame that supports the photoconductive element. The tank is provided with holder support members for supporting a blade holder which in turn holds the cleaning blade, and pins individually engageable with retaining members, which are securely mounted in predetermined portions of the frame, when the tank is rotated toward the photoconductive element until the edge of the cleaning blade assumes an accurate position relative to the photoconductive element in contact with the latter. The holder support members and the pins are provided in different portions of the tank.
With the prior art cleaning device described above, the force urging the operating edge of the cleaning blade against the photoconductive element cannot be maintained adequate and constant unless the various structural members, especially, holder support members mounted on the tank, pins and retaining members mounted on the frame, are positioned relative to each other with extreme accuracy. It is difficult, however, to assemble such members in their predetermined positions while accurately positioning them relative to each other. Further, the relative position is apt to be affected as the cleaning device is operated for a long period of time.
Thus, there is an increasing demand for a cleaning device whose cleaning blade can be positioned accurately and stably relative to a photoconductive element by maintaining various structural members in an accurate relative position and, yet, assembling the individual members in predetermined positions with ease.